Trowbridge Lake

Trowbridge Lake sits at the top of the Minnesota PCA grading rubric with an A, a mark reached by the cleanest lakes in Minnesota. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. At 76 ft of maximum depth, Trowbridge Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. The lake's 621 acres and 8.8 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Among the 97 graded lakes in Otter Tail County, Trowbridge Lake sits at rank 36, above the county median.

No invasive species are currently listed at Trowbridge Lake — the lake remains off the Minnesota infested-waters roster. The fishery includes walleye alongside the lake's other 13 documented species — a notable draw for Minnesota anglers. Public access is available — the lake is on the Minnesota PCA public-access list. The lake has a partial ice record — 10 observed ice-outs, centered near Apr 25. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.